Connecting hosts to storage over a network is a basic function of a SAN (Storage Area Network) that requires configuration of several entities: the hosts, the storage system and the Fibre-Channel switches that facilitate communication between hosts and the storage system.
To restrict host access to storage arrays, the Fibre channel switches are configured with zoning. Zoning is a configuration, performed by a system administrator (human) in the switch, for allowing certain hosts or host ports to forward traffic to certain destination ports in the storage system. In addition, an equivalent configuration, known as LUN mapping (also called LUN masking), is also required to be defined in the storage system, so as to ensure that the authorized host has access only to a predefined set of LUNs presented by the certain destination ports.
Since the LUN mapping information configured in the storage system has all the information required to create a zone in the switch, a new standard called Target Driven Zone (TDZ) was defined to allow the storage system to perform the zoning tasks (called Peer Zones) in the switches. Thus, once the storage system is configured with the LUN mapping, where a host port is associated with one or more storage (target) ports, the storage system can communicate with the SAN fabric for creating a zone automatically, for associating the storage port (known in TDZ as “principal N_Port”) and the host port(s) (known in TDZ as “peers”) that should be allowed to access the storage port. TDZ commands includes: add a peer zone, replace a peer zone and remove a peer zone.